Direct surface sampling is a simple, cost-effective, and easy-to-operate technique that is used to analyze chemical and biochemical compounds from a variety of surface types such as paper, thin layer chromatography plates, tissue sections, plant material, technical surfaces such as polymers, or metals. Physical, chemical and/or optical methods can be used to locate, visualize detect and quantitate analytes on technical and biological surfaces. More recently, interfaces have been developed that allow such surfaces to be sampled with mass spectrometry by means of a liquid extraction on the surface and subsequent ionization in the source of the MS, which can be with or without liquid chromatography separation.